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| United States Patent |
5,675,039
|
|
Stults
, et al.
|
October 7, 1997
|
Bis-m-benzotrifluoride compounds
Abstract
Disclosed are bis-meta-benzotrifluoride compounds having the general
formula
##STR1##
where each A is independently selected from the group consisting of
NO.sub.2, NH.sub.2, and NH.sub.3.sup.+ Z.sup.-, Z.sup.- is an anion and B
is selected from the group consisting of O, CO, S, SO, and SO.sub.2. The
diamine compounds are useful as monomers in making polyimides,
polyamide-imides, and polyamides.
| Inventors:
|
Stults; Jeffrey S. (1042 Baseline Rd., Grand Island, NY 14072);
Lin; Henry C. (1971 Ruth Rd., Grand Island, NY 14072);
Buchanan; Robert A. (2227 Center Ter. #1, Grand Island, NY 14072)
|
| Appl. No.:
|
554222 |
| Filed:
|
April 15, 1996 |
| Current U.S. Class: |
564/328; 564/430; 568/30; 568/36; 568/44; 568/306; 568/585 |
| Intern'l Class: |
C07C 225/22; C07C 317/36 |
| Field of Search: |
564/430,328
|
References Cited
U.S. Patent Documents
| 4996278 | Feb., 1991 | Lee | 528/26.
|
| 5061781 | Oct., 1991 | Leone-Bay et al. | 528/179.
|
| 5484879 | Jan., 1996 | Buchanan et al. | 528/353.
|
Primary Examiner: Raymond; Richard L.
Attorney, Agent or Firm: Fuerle; Richard D., Cookfair; Arthur S.
Parent Case Text
This application is a division of application Ser. No. 07/594,479, filed
Oct. 9, 1990, now U.S. Pat. No. 5,498,691, which is a continuation-in-part
of application Ser. No. 07/394,990, filed Aug. 17, 1989, now abandoned.
Claims
We claim:
1. A meta-benzotrifluoride compound having the general formula
##STR12##
where each A is independently selected from the group consisting of
NH.sub.2 and NH.sub.3 .sup.+ Z.sup.-, Z.sup.- is an anion, and B is
selected from the group consisting of O, CO, S, SO, and SO.sub.2.
2. A compound according to claim 1 wherein A is NH.sub.2 and B is S.
3. A compound according to claim 1 wherein A is NH.sub.2 and B is SO.
4. A compound according to claim 1 wherein A is NH.sub.2 and B is SO.sub.2.
5. A compound according to claim 1 wherein A is NH.sub.3.sup.+ Z.sup.- and
B is O.
6. A compound according to claim 1 wherein A is NH.sub.3.sup.+ Z.sup.- and
B is CO.
7. A compound according to claim 1 wherein A is NH.sub.3.sup.+ Z.sup.- and
B is S.
8. A compound according to claim 1 wherein A is NH.sub.3.sup.+ Z.sup.- and
B is SO.
9. A compound according to claim 1 wherein A is s NH.sub.3.sup.+ Z.sup.-
and B is SO.sub.2.
10. A meta-benzotrifluoride diamine having the general formula
##STR13##
11. A meta-benzotrifluoride diamine having the general formula
##STR14##
Description
BACKGROUND OF THE INVENTION
This invention relates to novel bis-m-benzotrifluoride compounds. In
particular, it relates to bis-m-benzotrifluoride diamines, precursors for
making the diamines, and to polymers made from the diamines.
Polyimides are condensation polymers usually made by reacting a primary
diamine with a dianhydride or tetracarboxylic acid. Aromatic polyimides,
where both the diamine monomer and the dianhydride or tetracarboxylic acid
monomer are aromatic, exhibit outstanding mechanical properties and
excellent thermal and oxidative stability. They are widely used in place
of metals and glass in high performance applications throughout the
electrical, electronic, automotive, aerospace, and packaging industries.
The properties of a particular polyimide depend, of course, on the
particular diamines and dianhydrides or tetracarboxylic acids used in
making it. Properties that are very useful in the electronics industry
include a high solubility of the polyimide in organic solvents and a low
dielectric constant. If the polyimide is to be used as a film, it is
desirable that it be colorless and transparent so that the underlying
substrate is visible and undistorted.
SUMMARY OF THE INVENTION
We have discovered and made a new class of diamines, and precursors for
making those diamines, which are very useful as monomers in making
polyimides. The diamines of this invention contain two benzotrifluoride
groups which give the resulting polyimides excellent electronic
properties, particularly a high solubility in organic solvents and a low
dielectric constant. Unlike other benzotrifluoride diamines known in the
art, the benzotrifluoride diamines of this invention are
meta-benzotrifluoride diamines which means that the substituents on the
benzene ring are in the 1,3,5 positions. Because the substituents are
meta, the resulting polyimides are much more stable than similar, but
non-meta, benzotrifluoride diamines.
DESCRIPTION OF THE INVENTION
The novel meta-benzotrifluoride compounds of this invention have the
general formula
##STR2##
where A is NO.sub.2, NH.sub.2, or NH.sub.3.sup.+ Z.sup.-, and B is O, CO,
S, SO, or SO.sub.2. The nitro compounds (where A is NO.sub.2) are
intermediate compounds used to make the diamine. When A is NH.sub.3.sup.+
Z.sup.-, an amine salt is formed where Z is an anion. Examples of suitable
anions include chloride, bromide, sulfate, and bisulfate. The chloride
anion is preferred as compounds necessary to make the chloride salt are
inexpensive and readily available. In the above formula, B is preferably
O, CO, or SO.sub.2 as those compounds are the most useful in making
polyimides.
The diamines of this invention can be prepared by a variety of methods, the
appropriateness of a method depending upon the particular diamine that is
being prepared. The ether (where B is O) can be prepared by beating
3,5-dinitrobenzotrifluoride in an organic solvent in the presence of water
and about two equivalents (based on the product weight) of potassium or
cesium fluoride which results in the dinitrodibenzotrifluoride ether:
##STR3##
1,1'-oxybis(3-nitro-5-trifluoromethyl) benzene In this reaction, it is
preferable to use potassium fluoride as a catalyst and
N,N-dimethylformamide (DMF) as a solvent and to heat at a temperature
between about 120.degree. and 160.degree. C. The reaction also produces
small amounts of higher ethers.
The ether can also be prepared by heating a nitro benzotrifluoride compound
having the formula
##STR4##
where x is NO.sub.2, Cl, F, or a mixture thereof, with potassium fluoride,
cesium flouride, or a mixture thereof, as described in copending
application Ser. No. 394,986, filed Aug. 17, 1989, now U.S. Pat. No.
4,990,670, by the same inventors, herein incorporated by reference.
The diamine can be prepared from the corresponding dinitro compound by
heating in a reducing agent, such as about 10 to about 50% iron and about
1 to about 20% hydrochloric acid:
##STR5##
4,4'-oxybis(3-trifluoromethyl)-benzamine That reaction can be performed at
a temperature of about 0 to about room temperature; ammonium sulfide can
also be used as a reducing agent. The presence of an acid in the reduction
reaction results in the formation of an amide salt (i.e., A is
NHNH.sub.3.sup.+ Z.sup.-). The amine salt can be easily converted to the
amine by the addition of any base such as sodium hydroxide, triethyl
amine, or pyrridine.
The ketone diamine (where B is CO) can be prepared by reacting
dibenzotrifluoride ketone with fuming nitric acid in the presence of
fuming sulfuric acid to first produce the dinitro ketone:
##STR6##
The reaction should be conducted at a temperature of less than 60.degree.
C. to prevent the formation of undesirable products.
The dinitro ketone can be reduced by the same reduction reaction described
hereinabove to produce the diamino ketone, 3,3'-ketobis
(5-trifluoromethyl)-benzamine (KBABTF).
The sulfide compound (where B is S) can be prepared by reacting
dinitrobenzotrifluoride with sodium sulfide or potassium sulfide to first
produce the dinitro sulfide:
##STR7##
1,1'-thiobis(3-nitro-5-trifluoromethyl)-benzene That reaction can be
conducted at about 150.degree. C. for about four hours and can be followed
by gas chromatograph (GC). The yield from that reaction is about 10%. The
dinitro sulfide can be reduced to the diamino sulfide by the reduction
reaction hereinbefore described.
The sulfoxide (where B is SO) can be made by oxidizing the diamino sulfide
compound. This can be accomplished with an oxidizing agent such as
hydrogen peroxide or, more preferably, metachloroperbenzoic acid, at a
temperature of less than 0.degree. C.
The sulfone compound (where B is SO.sub.2) can be prepared by reacting
benzotrifluoride, meta-chloride with sodium sulfide to prepare
dibenzotrifluoride sulfide:
##STR8##
This reaction is performed in an organic solvent such as NMP at a
temperature of about 170.degree. C. In the next step, the sulfide is
oxidized to the sulfone using an oxidizing agent such as 30% hydrogen
peroxide in acetic acid in a concentration of 30%:
##STR9##
These first two steps are reactions known in the art, see Example 17 of
U.S. Pat. No. 3,538,166 and an article by J. R. Campbell and R. E. Hatton
in J. Org. Chem. 26, p. 2480 (1961).
In the next step, the sulfone is nitrated using a mixture of at least two
equivalents nitric acid (density--1.5 g/cc or greater) and at least two
equivalents sulfuric acid containing up to 65% SO.sub.3 at a temperature
of less than 80.degree. C.:
##STR10##
1,1'-sulfonyl bis(3-nitro-5-trifluoromethyl) benzene
Finally, the dinitro compound is reduced to the amine compound by the
hereinabove-described reduction reaction.
A second way of making the sulfone is described in copending patent
application Ser. No. 394,988, filed Aug. 17, 1989, now U.S. Pat. No.
5,304,687, by Jeffrey S. Stults, titled "Method of Making Dinitro and
Diamino Meta-Bisbenzotrifluoride Compounds," herein incorporated by
reference. Briefly, dibenzotrifluoride sulfide is reacted with fuming
nitric acid in the presence of fuming sulfuric acid at a temperature of
about 0.degree. to about 75.degree. C.:
##STR11##
The diamines of this invention are useful in making polyimides,
polyamide-imides, and polyamides. The polyimides can be prepared by
well-known reactions of diamines with dianhydrides or tetracarboxylic
acids, substituting the diamines of this invention for the diamines that
would otherwise be used. While non-aromatic dianhydrides can be used,
aromatic dianhydrides are preferred because the polyimides have better
thermal properties. Examples of suitable dianhydrides include
oxydiphthalic anhydride (ODPA), biphenyl dianhydride (BPDA), benzophenone
tetracarboxylic dianhydride (BTDA), pyromellitic dianhydride (PMDA), and
"6-F" dianhydride 5,5'-›2,2,2-trifluoro-1-(trifluoromethyl)ethylidene!
bis-1,3-isobenzofurandione). Generally, the reaction of the diamine and
the dianhydride or tetracarboxylic acid will proceed at room temperatures
or under mild heat. Dianhydrides are preferred to tetracarboxylic acids as
the reaction proceeds more easily. Polyimides can also be prepared from
half esters of tetracarboxylic acids and from hydrolyzed nitriles, but the
reactions are more difficult. Polyamideimides can be prepared by reacting
the diamines with a trifunctional anhydride or carboxylic acid such as
trimellitic anhydride or trimellitic acid. Polyamides can be prepared by
reacting the diamine with a dicarboxylic acid or an acid halide, and
polyurethanes can be prepared by reacting the diamines with diisocyanate.
The following examples further illustrate this invention.
EXAMPLE 1
Preparation of 1,1'-sulfonyl-bis(3-nitro-5-trifluoromethyl)benzene
To a one liter flask was charged nitric acid (fuming, 50 ml.) and sulfuric
acid (20% oleum, 130 ml.) and the flask was cooled to 0.degree.-5.degree.
C. with an ice bath. 1,1'-Sulfonyl-bis(3-trifluoromethyl)benzene (23.5 g.)
was added. The reaction mixture was heated to 65.degree. C. and after 3
hours GC analysis indicated complete consumption of the sulfone and
appearance of
1-(3-nitro-5-trifluoromethylphenylsulfonyl)-3-trifluoromethylbenzene.
Nitric acid (fuming, 75 ml.) and sulfuric acid (20% oleum, 195 ml.) were
added and the reaction was heated for an additional 5 hours. The reaction
mixture was purged with nitrogen until evolution of nitrogen oxides
ceased. The reaction mixture was poured into 400 g. ice and the resulting
solid collected. The solid was washed with cold water to give 26.8 g (91%
yield) of the desired 1,1-sulfonyl-bis(3-nitro-5-trifluoromethyl)benzene.
EXAMPLE 2
Preparation of 1,1'-oxybis(3-nitro-5-trifluoromethyl) benzene
To a 500 ml round bottom flask was charged 3,5-dinitrobenzotrifluoride
(25.1 g.), potassium fluoride (21.2 g), water (2.4 ml.), and
dimethylformamide (DMF, 125 ml.). The reaction was heated to 160.degree.
C. for 24 hours. The reaction mixture was diluted with water (400 ml.) and
extracted with ether (3.times.150 ml.). The ether was dried with magnesium
sulfate and cooled to 5.degree. C. and the resulting solid collected to
give a total of 11.3 g (53.8% yield) of the desired
1,1-oxy-bis(3-nitro-5-trifluoromethyl)benzene.
EXAMPLE 3
Preparation of 4,4'-oxybis(3-trifluoromethyl)-benzamine hydrochloride
To a flask containing about 0.88 g of the product of Example 2 was added
1.8 g iron powder and 10 ml of 50% ethanol. The mixture was heated to
reflux and 1.5 ml of 50% ethanol and 0.1 ml concentrated HCl was added.
The mixture was refluxed for 2 hours. The iron powder was filtered and
washed with 95% ethanol. The ethanol was evaporated, water was added, and
the product was extracted with ether. Hydrogen chloride was bubbled
through the ether solution of the product and 0.38 g of
4,4'-oxybis(3-trifluoromethyl)-benzamine hydrochloride (43% yield) were
collected.
EXAMPLE 4
Preparation of 1,1'-sulfonyl-bis (3-nitro-5-trifluoromethyl)benzene
To a cooled (10.degree. C.) 250 ml. round bottom flask containing nitric
acid (fuming, 50 ml.) and sulfuric acid (20% oleum, 90 ml.) was added
1,1'-thio-bis(3-trifluoromethyl)benzene (10 g). The reaction mixture was
held at low temperature until sulfoxide formation was complete (circa 1.5
hrs) and then heated to 35.degree. C. The reaction mixture was then heated
slowly to 65.degree. C. Analysis of the reaction mixture indicated a
mixture of nitrated compounds had formed. The oxidation and nitration
reactions were carried to completion by heating the reaction mixture to
85.degree. C. The reaction mixture was then poured onto ice and the solid
collected and washed with cold water to give
1,1'-sulfonyl-bis)3-nitro-5-trifluoromethyl)benzene as a white solid (7.16
g, 52% yield).
EXAMPLE 5
Preparation of 1,1'-sulfonyl-bis (3-nitro-5-trifluoromethy)benzene
To a cooled (10.degree. C.) 250 ml. round bottom flask containing nitric
acid (fuming, 50 ml.) and sulfuric acid (20% oleum, 90 ml.) was added
1,1'-sulfonyl-bis(3-trifluoromethyl)benzene (27.3 g). The reaction mixture
was heated to 75.degree. C. and additional nitric acid (52 ml.) and
sulfuric acid (130 ml.) were added. The reaction was heated for 7 hours at
75.degree. C. and additional nitric acid (3 ml.) and sulfuric acid (3 ml.)
was then added. The reaction mixture was heated for an additional 2 hours.
The reaction mixture was poured onto 600 g. ice and the collected solid
was washed with cold water to give
1,1'-sulfonyl-bis(3-nitro-5-trifluoromethyl)benzene as a white solid (27.2
g, 79% yield). Additional
1,1'-sulfonyl-bis(3-nitro-5-trifluoromethyl)benzene could be obtained from
an ether extraction of the filtrate (4.4 g, 92% total yield).
EXAMPLE 6
Preparation of 5,5'-bistrifluoromethy-3,3'-dinitro-benzophenone
To a 250 ml. flask containing nitric acid (fuming 33.8 g.) and sulfuric
acid (20% oleum, 83 ml.) was added first 3,3'-bistrifluoromethyl
benzophenone (40.6 g.) followed by additional sulfuric acid (50 ml.). The
temperature was maintained at less than 40.degree. C. by cooling with an
ice water bath. The reaction mixture was heated at 40.degree. C. for
approximately 3 hours. The reaction mixture was poured onto 300 g. ice and
the precipitate was collected, washed with cold water, and dried to give
5,5'-bistrifluoromethyl-3,3'-dinitro benzophenone (51.4 g., 82% yield).
EXAMPLE 7
Preparation of 3,3'-thiobis(3-nitro-5-trifluoromethyl)benzene
A 25 ml 2-necked flask was charged with 0.44 g Na.sub.2 S nonahydrate, and
2 ml NMP. The mixture was heated to 210.degree. C. to remove water and
0.99 g of meta-dinitrobenzotrifluoride was added. The yield of
3,3'-thiobis(3-nitro-5-trifluoromethyl)benzene was about 10%.
EXAMPLE 8
Preparation of 5,5'-bistrifluoromethyl-3,3'-diaminobenzophenone,
hydrochloride salt
To a round bottom flask containing ethanol (80 ml.) and
5,5'-bistrifluoromethyl-3,3'-dinitro benzophenone (4.9 g.) at 50.degree.
C. was added 10% palladium on carbon (0.05 g.) followed by hydrazine (3.0
ml.). The reaction temperature was raised to 70.degree. C. and the
reaction stirred for 2 hours. The reaction mixture was filtered through
filter aid, the ethanol removed under reduced pressure, and replaced with
ethyl acetate (90 ml.). The ethyl acetate was washed with a saturated
sodium chloride solution (10 ml.), followed by water (10 ml.) and
saturated sodium chloride solution. The ethyl acetate was dried (sodium
sulfate) and evaporated to give a residue (3.62 g.). The residue was
dissolved in ether and the ether was washed with 10% aqueous HCl followed
by a 5% aqueous bicarbonate solution. Hydrogen chloride gas was then
bubbled through the ether solution to give
5,5'-bistrifluoromethyl-3,3'-diamino benzophenone, hydrochloride salt as a
precipitate (2.1 g, 50% yield).
EXAMPLE 9
Preparation of 1,1'-oxybis(3-nitro-5-trifluoromethyl)benzene
The following experiment was conducted to determine if the other leaving
groups could be used in place of nitro for the preparation of
1,1-oxybis(3-nitro-5-trifluoromethyl)benzene. To a solution of
3-fluoro-5-nitrobenzotrifluoride, isolated by distillation from the mother
liquor of Example 2, in DMF (5 ml.) was added potassium fluoride (0.7 g.).
The suspension was heated to 150.degree. C. and 2 drops of water were
added. The reaction progress was monitored by gas chromatography (GC).
After 7 hours, GC analysis indicated a 0.17:1 mixture of
1,1-oxybis(3-nitro-5-trifluoromethyl)benzene to the starting fluoride had
been obtained. This ratio increased to 2.1:1 after heating for 17.5 hours.
EXAMPLE 10
Preparation of Polyimide From 5,5'-oxybis (3-trifluoromethyl)
benzamine(135-OBABTF) and ODPA
ODPA (11.69 g) was added to a stirred solution of dry dimethylacetamide
(76.1 g) containing 12.68 g of the diamine 135-OBABTF. The solution was
stirred at room temperature under a nitrogen atmosphere for 16 to 24
hours. After filtration, a portion of the resulting poly(amic acid)
solution was spread on a glass plate with a doctor blade to a 0.9 to 1.1
mil thick polyimide film after curing. The plate was placed in a dust-free
chamber and warm nitrogen was passed over the plates until the film was no
longer tacky. The plates were heated at a rate of 2.degree. C. per minute
and held at 100.degree. C., 200.degree. C., and 300.degree. C. for 0.5 to
1 hour each to effect imidization. After cooling, the films were removed
by soaking in warm to hot water. The cured film was transparent,
creasible, and tough. T.sub.g =210.degree. C., dielectric constant=3.10 (1
MHz at 50% relative humidity), oxygen index=45.3%, 84% transmittance at
500 nm, and tensile modulus 480,000 psi.
EXAMPLE 11
Preparation of Polyimide From 135-OBABTF AND BTDA
9.20 g 135-OBABTF, 8.77 g BTDA, and 84.3 g DMAc were used as described
above to give a tough, transparent polyimide with T.sub.g =225.degree. C.,
dielectric constant=2.99 (1 MHz, 50% relative humidity), moisture
regain=0.46% (50% relative humidity), dissipation factor=0.0052 (1 MHz at
50% relative humidity), oxygen index=47.3%, and transmittance at 500 nm.
EXAMPLE 12
Preparation of Polyimide From 135-OBABTF AND BPDA
15.39 g 135-OBABTF, 13.40 g BPDA, and 90.0 g DMAc were used as described
above to give a tough, transparent poIyimide with T.sub.g =240.degree. C.,
dielectric constant=3.13 (1 MHz, 50% relative humidity), moisture
regain=0.44% (50% relative humidity), dissipation factor=0.0045 (1 MHz at
50% relative humidity), oxygen index=49.5%, and 86% transmittance at 500
nm.
EXAMPLE 13
Preparation of Polyimide From 135-OBABTF AND 6FDA
9.93 g 135-OBABTF, 13.11 g 6FDA, and 86.2 g DMAc were used as described
above to give a tough, transparent polyimide with T.sub.g =230.degree. C.,
dielectric constant=2.62 (1 MHz, 50% relative humidity), moisture
regain=0.33% (50% relative humidity), dissipation factor=0.0065 (1 MHz at
50% relative humidity), and 88% transmittance at 500 nm.
EXAMPLE 14
Preparation of Polyimide From 135-SBABTF AND BTDA
1.4832 g 135-SBABTF, 1.4152 g BTDA, and 14.5 ml DMAc were used as described
in Example 13 to give a poly(amic acid) with an inherent viscosity of
0.40. Upon curing as described above, a clear polyimide film was formed.
EXAMPLE 15
Preparation of Polyimide From 135-KBABTF AND ODPA
0.4769 g 135-KBABTF, 0.5151 g ODPA, and 5.0 ml DMAc were used as described
above to give a poly(amic acid) with an inherent viscosity of 0.23. Upon
curing as described above, a polyimide film was formed which was soluble
in chloroform.
EXAMPLE 16
Preparation of Polyimide From 135-OBABTF AND ODPA
12.68 g 135-OBABTF, 11.69 g ODPA, and 76.1 g DMAc were used as described
above to give a tough, transparent polyimide with a T.sub.g =210.degree.
C., dielectric constant=3.10 (1 MHz, 50% relative humidity), moisture
regain=0.33% (50% relative humidity), oxygen index=45.3%, thermal
decomposition temperature of 548.degree. C., and 78% transmittance at 500
nm.
EXAMPLE 17
Preparation of polyimides from 135-OBABTF AND BTDA
9.20 g 135-OBABTF, 8.77 g BTDA, and 84.3 g DMAc were used as described
above to give a tough, transparent, polyimide with a T.sub.g =225.degree.
C., dielectric constant=2.99 (12 MHz, 50% relative humidity), moisture
regain=0.46% (50% relative humidity), oxygen index=47.3%, thermal
decomposition temperature at 536.degree. C., and 78% transmittance at 500
nm.
EXAMPLE 18
Preparation of Polyimide From 135-OBABTF AND BTDA
15.39 g 135-OBABTF, 13.40 g BTDA, and 90.0 DMAc were used as described
above to give a tough transparent polyimide with at T.sub.g =240.degree.
C., dielectric constant=3.13 (1 MHz, 50% relative humidity), moisture
regain=0.44% (50% relative humidity), oxygen index=49.5%, thermal
decomposition temperature of 545.degree. C., and 86% transmittance at 500
nm.
EXAMPLE 19
Preparation of Polyimide From 135-OBABTF AND BTDA
9.93 g 135-OBABTF, 13.11 g BTDA, and 86.2 g DMAc were used as described
above to give a tough, transparent polyimide with a T.sub.g =230.degree.
C., dielectric constant=2.62 (1 MHz, 50% relative humidity), moisture
regain=0.33% (50% relative humidity), thermal decomposition temperature of
528.degree. C., and 88% transmittance at 500 nm.
COMPARATIVE EXAMPLES
EXAMPLE 20
Preparation of Polyimide From 124-OBABTF AND ODPA
12.43 g ODPA was added to a stirred solution of dry dimethylacetamide
(121.8 g) containing 13.48 g of the diamine 124-OBABTF. The solution was
stirred at room temperature under a nitrogen atmosphere for 12 to 20
hours. After filtration, a portion of the resulting poly(amic acid)
solution was spread on glass plates with a doctor blade to give a 0.9 to
1.1 mil thick polyimide film after curing. The plates were placed in
dust-free chamber and warm nitrogen was passed over the plates until the
films were no longer tacky. The plates were heated at the rate of
2.degree. C. per minute and held at 100.degree. C., 200.degree. C. and
300.degree. C. for 0.5 to 1 hour each. After cooling, the films were
removed by soaking in warm to hot water. The cured film was transparent,
tough, and light yellow in color. The T.sub.g =255.degree. C., dielectric
constant=3.14 (1 MHz, 50% relative humidity), moisture regain=0.54% (50%
relative humidity), and tensile modulus 457,000 psi.
EXAMPLE 21
Preparation of Polyimide From 124-OBABTF AND BTDA
10.08 g 124-OBABTF, 9.66 g BTDA, and 123.3 g DMAc were used as described
above to give a tough, transparent polyimide with a T.sub.g =265.degree.
C., dielectric constant=3.22 (1 MHz, 50% relative humidity), moisture
regain=0.70% (50% relative humidity), and 70% transmittance at 500 nm.
EXAMPLE 22
Preparation of Polyimide From 124-OBABTF AND BPDA
10.01 g 124-OBABTF, 8.76 g BPDA, and 117.1 DMAc were used as described
above to give a tough, transparent polyimide with a T.sub.g =290.degree.
C., dielectric constant=3.20 (1 MHz, 50% relative humidity), moisture
regain=0.67% (50% relative humidity), and 78% transmittance at 500nm.
EXAMPLE 23
Preparation of Polyimide From 124-OBABTF AND 6FDA
6.86 g 124-OBABTF, 9.06 g 6FDA, and 99.3 DMAc were used as described above
to give a tough, transparent polyimide with at T.sub.g =295.degree. C.,
dielectric constant=0.53% (1 MHz, 50% relative humidity), and 88%
transmittance at 500 nm.
EXAMPLE 24
Preparation of Polyimide From 124-OBABTF AND 6FDA
14.50 g 124-OBABTF, 9.41 g 6FDA, and 112.0 g DMAc were used as described
above to give a tough, transparent polyimide with a T.sub.g =315.degree.
C., dielectric constant=3.16 (1 MHz, 50% relative humidity), moisture
regain=1.12% (50% relative humidity), thermal decomposition temperature of
548.degree. C., and 80% transmittance at 500 nm.
The following table summarizes the results of Examples 10 to 24 and
compares properties of polyimides prepared from 135 OBABTF with the
properties of polyimides prepared from 24 OBABTF
__________________________________________________________________________
ODPA BTDA BPDA 6-FDA
135 124 135 124 135 124 135 124
OBABTF
OBABTF
OBABTF
OBABTF
OBABTF
OBABTF
OBABTF
OBABTF
__________________________________________________________________________
Glass transition temperature (.degree.C.)
210 255 225 256 240 290 230 295
Dielectric constant (ASTM D150-87)
3.1 3.14 2.99 3.22 3.13 3.2 2.62 2.76
Moisture Regain (50% RH)
0.0033
0.0054
0.0046
0.007
0.0067
0.0067
0.0033
0.0053
Transmission (500 nm)
84% 85% 78% 70% 86% 78% 88% 88%
Tensile modulus (psi)
480000
457000
10% weight loss (3.degree./min, air) 528.degree. C.
524.degree. C.
__________________________________________________________________________
In the above table, a low glass transition temperature, T.sub.g, is
desirable because polyimides having a low T.sub.g are more easily
processed. The dielectric constant and the moisture regain should also be
low for better electrical insulating properties. High light transmission
is desirable for optical applications and for aesthetic reasons. A high
tensile modulus provides strength and a high weight loss indicates thermal
stability. the above table shows that the polyimides made from 135 OBABTF
(i.e., the polyimides of this invention) have superior properties to
polyimides made from 124 OBABTF,
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